


The Physics of Crystals

by tptigger



Series: Super Grover: Companion [2]
Category: Doctor Who (2005), Sesame Street (TV)
Genre: Challenge fic, Gen, Super Grover, signing crystals of Pish
Language: English
Status: Completed
Published: 2018-03-02
Updated: 2018-03-02
Packaged: 2019-03-26 01:02:25
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 951
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13846764
Author URL: https://archiveofourown.org/users/tptigger/pseuds/tptigger
Summary: The Doctor takes Super Grover to see the singing crystals of the third moon of Pish.





	The Physics of Crystals

**Author's Note:**

  * For [KerrAvonsen](https://archiveofourown.org/users/KerrAvonsen/gifts).



> This was written in 2009 to a challenge by kerravonsen:  
> Fandom/character(s): The Doctor (Doctor Who) and Super Grover (Sesame Street)  
> Time of day: low noon (the noon of the smaller sun of a binary star system)  
> Weather: frosty  
> Three objects to include: singing crystals, a broken harp string, tuning fork
> 
> I thought it wise to put it here instead of letting it languish on Dreamwidth.

"Boy, it's very hot on this planet," Grover said, as he hopped out of the TARDIS.

"That helmet's soaking up the sun's rays," The Doctor said.

"Oh, no," said Grover, "I'm not falling for that again. On the last planet you got me out of my disguise and I risked exposing my secret identity when we had to save those Alpha Centaurians from those renegade Judoon."

"Yes, you do seem to be quite the Judoon magnet," The Doctor said.

"They were after Gonzo!" Grover said.

"I should point out that this is only low noon, come high noon, it's going to be even hotter," the Doctor said.

"High noon?" Grover repeated. "Low noon?"

The Doctor pointed up. "The lesser sun is at noon, the highest point in its trip through the sky, low noon. When the larger sun is in the highest place, that is to say, high noon, it will get hotter."

"Nevertheless, a super hero never removes his costume," Grover said resolutely. "Besides, you're probably twice as hot in that suit."

"I don't feel the heat the way you do," the Doctor replied.

Grover studied him carefully. "If you insist. What wrong are we going to right here?"

"Who said anything about righting wrongs, I thought we could do with a trip to the Singing Crystals of The Third Moon of Pish, now that it's back and everything."

"Back?" Grover echoed.

"Never mind, hurry up, we're going to be late!" the Doctor said, nearly breaking into a run.

Grover rolled his eyes. "And you wanted me to change." He scooped up the Doctor and launched into the air. "Where to, Doctor?"

"Put me down, please, Grover, you'll freak out the natives," the Doctor said patiently.

"Okay," Grover said, landing hard.

"Ow!"

"Sorry!"

"Come on, the opera house is this way," the Doctor said.

* * *

Grover and the Doctor settled into the middle of one of the back rows just as a green woman wearing a flowing purple gown took the stage.

"I thought you said there were singing crystals," Grover whispered.

"Patience, mon petite blue," Doctor said.

The woman sat down at a harp, running her fingers over the strings. One snapped, and she winced. Grover rose, as if running to help.

"It's all right, Grover, she's made of sterner stuff than that," the Doctor said.

"Why don't the crystals start singing without her?" Grover asked, fidgeting impatiently.

The Doctor blinked at Grover. "The crystals don't sing. They harmonically resonate."

"Harmonica...."

"Close, harmonics," the Doctor said. "The frequency of the harp music..."

"Frequency?" Grover interrupted.

The Doctor scrubbed a hand through his hair. "Sounds are like waves."

"Ocean waves?" Grover asked.

"Very similar," the Doctor said. He rooted through the pockets of his jacket, producing a bit of string. "I can make waves on the string too. It's the same principle. I disturb the string by making it vibrate." He tweaked the string. "Sound does the same thing to the air, but we can't see it," the Doctor said. "Frequency is how fast it's vibrating. See how when I speed up the distance between the tops of each wave is closer together."

"Yes," Grover said.

"Well, when the sound waves reach an exact frequency, and they hit the crystals, the crystals vibrate in sync to the them and make more sound."

"That sounds very interesting," Grover said, starting to fidget again now that the Doctor was no longer holding his attention. "What's she doing now?"

The harpist had finished restringing the instrument and had produced a metal object with two prongs.

"That's a tuning fork," the Doctor said. "That's for making sure the harp sounds right."

"Are you sure it's not a cold-making machine?" Grover asked. "I think it's getting colder in here."

The Doctor looked up. "Oh, oops. I got my moons of Pish backwards. Lesser noon comes *after* high noon. It's getting colder because the sun is going down."

Grover sighed. "I'd complain, but you did manage to get us on the right planet for once."

The Doctor raised an eyebrow at Grover, but didn't say anything.

"Ah, here we go," The Doctor said as the harpist raised her hands to the strings.

* * *

Grover was practically running as they left the amphitheater about an hour later.

The Doctor glanced behind him. "Is someone following us?" he asked.

"No, Doctor," Grover said, "but I'm going to freeze my cute, fuzzy pipic off if we don't get back to the TARDIS."

The Doctor looked at Grover quizzically. "You have a belly button?"

Grover rolled his eyes, and slowed down a bit. "Are you sure we can't just fly there?"

"Keep your voice down, Grover, the citizens of Pish feel that flying is bad luck."

Grover glanced over at the spaceport, then back at the Doctor. "I'd think you were making it up, except that they seem to believe that a bunch of shaking crystals are singing."

"What did you expect them to do?" The Doctor asked. "Gilbert and Sullivan?"

"Who?" Grover asked.

"They write operas," The Doctor said.

"That would make more sense than than them vibrating," Grover said.

The Doctor stared. "Grover, crystals are, by definition, inanimate objects. And even if we did meet a crystal creature, I doubt it would have a tongue and larynx capable of singing."

"There's singing lettuce on Sesame Street," Grover pointed out as they approached the TARDIS.

"If I didn't know better, I'd swear I picked you up in an alternate dimension," The Doctor said, opening the door.

"There are other dimensions, can we go to one?" Grover asked hopefully.

"No," The Doctor said. "I do know a planet of sentient trees if you'd like to visit that."

Grover smiled. "Let's go!"

End


End file.
